Neo Pangea built this code cracking game for National Geographic to help promote their new book series Explorer Academy.

"Adventure, danger, and a thrilling global mission await 12-year-old Cruz Coronado at the Explorer Academy, where he and 23 other kids from around the globe will train to become the next generation of great explorers. But in addition to making new friends and attending cool classes, Cruz must also unlock clues to his family’s mysterious past and tackle the biggest question of all: Who is out to get him … and why?"

In the game you need to rotate the wheels of the cipher, lock them in place and them start to decode the hidden messages. It starts off simple enough but soon you'll need to crack the codes on your own. If you have the books to hand, they can help.